When researchers investigated the way that people interact with products that they touched, they found that people were more likely to purchase the products they held for a longer period of time and they valued objects that they had held higher than objects they didn't hold or didn't hold as long. Touch is a powerful driving force in the attachments we make to people and things. The more the sales environment invites and encourages customers to hold or touch products or solutions, the more statistically likely they will be to ultimately make a purchase.

Source

Wolf, J. R., Arkes, H. R., & Muhanna, W. A. (2008). The Power of touch: An examination of the effect of physical contact on the valuation of objects. Judgement and Decision Making, 3(6), 476-482.